Question on ESC
08-12-2013, 11:30 AM
#1
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Question on ESC
I'm new to electrics, and I just finished setting up my first plane. I was setting up the receiver and servos when I realized that if I switched off my transmitter, the ESC consistently turns on full power to the engine. Lucky I just happened to have had my hand on the plane the first time that happened! I can't imagine this as anything other than a bad safety issue. What's up with that?
08-12-2013, 04:49 PM
#2
Well, it is very bad safety to turn off the Tx before the Rx. You found out what can happen.
Transmitter on first and last off. If you have the Rx on, it can get a signal from any where. That is why you turn the Rx off fist.
Tx on, Rx on, Rx off, Tx off.
This is the same as glow planes.
Buzz,
Transmitter on first and last off. If you have the Rx on, it can get a signal from any where. That is why you turn the Rx off fist.
Tx on, Rx on, Rx off, Tx off.
This is the same as glow planes.
Buzz,
08-12-2013, 06:38 PM
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Well, this isn't the first response like this I've gotten. It's not much of an explanation or solution though.
I'm no expert on RC radio technology, but the receiver can't just pick up a "signal" from anywhere. That's some magical omni-present stray signal that just happens to be on 2.4Ghz with exactly the right high tech encoding to command the receiver to send a full throw signal to just the ESC. Not 1/4 power, not full elevator, or rudder, this magical stray signal is always commanding full power only to the ESC?
BTW, if my transmitter happens to fail during flight or on the ground, how do propose that I switch off the receiver then, before the plane goes off out of control ... at full power? Going full throttle on a link failure is a safety issue pure and simple, and disconnecting the power isn't the solution. I would be very surprised if this is a normal as-designed behavior on all receivers/ESCs.
BTW, what bad safety risk do you think there is shutting off the transmitter on a glow plane that has the engine shut off?
I'm no expert on RC radio technology, but the receiver can't just pick up a "signal" from anywhere. That's some magical omni-present stray signal that just happens to be on 2.4Ghz with exactly the right high tech encoding to command the receiver to send a full throw signal to just the ESC. Not 1/4 power, not full elevator, or rudder, this magical stray signal is always commanding full power only to the ESC?
BTW, if my transmitter happens to fail during flight or on the ground, how do propose that I switch off the receiver then, before the plane goes off out of control ... at full power? Going full throttle on a link failure is a safety issue pure and simple, and disconnecting the power isn't the solution. I would be very surprised if this is a normal as-designed behavior on all receivers/ESCs.
BTW, what bad safety risk do you think there is shutting off the transmitter on a glow plane that has the engine shut off?
Last edited by mmabc; 08-12-2013 at 06:47 PM.
08-13-2013, 04:11 AM
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It's a Detrum ESC I got from HobbyKing. I can program brake setting, battery type, low voltage cutoff mode, cutoff threshold, startup mode, and timing. I can also adjust throttle range setting. I did that, no change.
It does have the following statement under "Protection function:"
Throttle signal loss protection: The ESC will reduce output power if throttle signal is lost for one second. Further loss for 2 seconds will cause it's output to be cutoff completely.
I'm curious what signal the receiver is sending when it loses link, if any? There's about a second delay after the transmitter switches off before the engine goes full power.
It does have the following statement under "Protection function:"
Throttle signal loss protection: The ESC will reduce output power if throttle signal is lost for one second. Further loss for 2 seconds will cause it's output to be cutoff completely.
I'm curious what signal the receiver is sending when it loses link, if any? There's about a second delay after the transmitter switches off before the engine goes full power.
08-13-2013, 05:50 AM
#6
Can program the receiver to kill throttle on signal loss? I think you should be able to. I remember with glow engines I would program the Rx to go to idle (debated with throttle kill) at signal loss.
That 'protection function' does not sound like much protection at all. I don't know much about hobby king products, I try to stay away.
Thanks for posting this - I imagine I have been taking the cutoff feature of my ESC's for granted. That scenario could be very bad especially with my bigger 10S airplanes.
That 'protection function' does not sound like much protection at all. I don't know much about hobby king products, I try to stay away.
Thanks for posting this - I imagine I have been taking the cutoff feature of my ESC's for granted. That scenario could be very bad especially with my bigger 10S airplanes.
08-13-2013, 11:02 AM
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That's an interesting thought. Looking at the manual for my Futaba 7C radio:
FailSafe (F/S ): instructs a receiver what to do in the event radio interference is received.
Adjustability:
• Only channel 3(throttle) may be set.
• The NOR (normal) setting holds the servo in its last commanded position.
• The F/S (FailSafe) function moves servo to a predetermined position.
• NOTE: the setting of F/S also applies to the Battery F/S(see below).
It's a used radio. I thought I reset it to factory settings, but now I don't remember. I'll check this when I get home tonight.
FailSafe (F/S ): instructs a receiver what to do in the event radio interference is received.
Adjustability:
• Only channel 3(throttle) may be set.
• The NOR (normal) setting holds the servo in its last commanded position.
• The F/S (FailSafe) function moves servo to a predetermined position.
• NOTE: the setting of F/S also applies to the Battery F/S(see below).
It's a used radio. I thought I reset it to factory settings, but now I don't remember. I'll check this when I get home tonight.
08-13-2013, 06:05 PM
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Well, I'm happy to say that was it. The radio was set to failsafe, or should I say fail dangerously? I don't know why it was. I thought I reset it to factory defaults, and I would be surprised if that was the default. Maybe I just inadvertently set it. Now that I know what it is, I can perhaps set failsafe to cut the throttle. I'll definitely be checking that setting for my other model configuration.
Anyway, thanks Joe, that was really bugging me!
Anyway, thanks Joe, that was really bugging me!
